Mechanism of hexavalent chromium removal by dead fungal biomass of Aspergillus niger

• Published in: Water research (Oxford) Vol. 39; no. 4; pp. 533 - 540
• Main Authors: Park, Donghee, Yun, Yeoung-Sang, Hye Jo, Ji, Park, Jong Moon
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-02-2005; Elsevier Science
• Subjects: Applied sciences; Aspergillus niger; Aspergillus niger - metabolism; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biomass; Biosorption; Biotechnology; Carcinogens, Environmental - isolation & purification; chemical speciation; chromium; Chromium - chemistry; Chromium - isolation & purification; Chromium - metabolism; desorption; Detoxification; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Fungi; heavy metals; Hexavalent chromium; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Industrial wastewaters; Kinetics; metabolic detoxification; pollutants; Pollution; Reduction; Spectrometry, X-Ray Emission; Temperature; Time; trivalent chromium; Waste Disposal, Fluid - methods; Wastewaters; Water Purification - methods; Water treatment and pollution; Hexavalent chromium; Fungi; Reduction; Biosorption; Detoxification; girds: Biosorption; Bioadsorbents; Biomass; Operating conditions; Biological purification; Chemical reduction; Aspergillus niger; Industrial waste water; Fungi Imperfecti; Kinetics; Waste water purification; Chromium VI; Thallophyta
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2004.11.002

When synthetic wastewater containing Cr(VI) was placed in contact with the dead fungal biomass of
Aspergillus niger, the Cr(VI) was completely removed from aqueous solution, whereas Cr(III), which was not initially present, appeared in aqueous solution. Desorption and X-ray photoelectron spectroscopy (XPS) studies showed that most of the Cr bound on the biomass was in trivalent form. These results indicated that the main mechanism of Cr(VI) removal was a redox reaction between Cr(VI) and the dead fungal biomass, which is quite different from previously reported mechanisms. The influences of contact time, pH, Cr(VI) concentration, biomass concentration and temperature on Cr(VI) removal were also evaluated. The Cr(VI) removal rate increased with a decrease in pH and with increases in Cr(VI) concentration, biomass concentration and temperature. Although removal kinetics was dependent on the experimental conditions, Cr(VI) was completely removed in the aqueous solution. In conclusion, a new mechanism of Cr(VI) removal by the dead fungal biomass has been proposed. From a practical viewpoint, this abundant and inexpensive dead fungal biomass has potential application in the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).